Rocks that initially form from deposition are known as sedimentary rocks. These rocks are created through the accumulation and compaction of mineral and organic particles, as well as the precipitation of minerals from water.
There are several types of sedimentary rocks:
- Clastic Sedimentary Rocks: These are formed from the accumulation of rock fragments or clasts. Common examples include sandstone, siltstone, and shale. They are categorized based on the size of the particles that compose them.
- Chemical Sedimentary Rocks: These rocks form when minerals precipitate directly from water. An example is limestone, which can form from the calcite that precipitates out of seawater.
- Organic Sedimentary Rocks: These are formed from the accumulation of plant or animal remains. Coal is a prime example, formed from compressed plant material over millions of years.
In summary, sedimentary rocks are primarily formed from deposition processes, including the settling of particles in various environments such as rivers, lakes, and oceans. Over time, these deposits are lithified, or turned into rock, through compaction and cementation.